The present invention relates generally to a system for detecting the material level in a container, and more particularly to an optical non-contact sensor system for measuring the volume of material within a container.
Conventional storage vessels, such as propane tanks, are beneficial both for their mobility and for their suitability to the energy needs of remote locations where access to other forms of energy is often unavailable or costly. It is desirable to be able to detect the volume of liquid in such a vessel at any specific time so as to schedule re-supply (sometimes referred to as re-charging) of the tank thereby to prevent emptying of the vessel (sometimes referred to as “running dry”.) Sensors for measuring the elevation of the upper surface of liquid contained in a vessel are known. In operation, such a sensor generates an electrical signal indicative of the quantity of liquid in the vessel. The signal is transmitted to an interface located externally of the vessel which communicates to a user the quantity of liquid in the vessel.
One such type of internal sensor is a float-type gauge. Such a gauge normally has limited accuracy because it contains moving parts such as the float and associated linkage for sensing vertical displacement of the float as the upper surface of the liquid rises and falls. With movement comes associated friction to which the moving parts are subjected thereby causing wear to the gauge and eventual degradation. Additionally, a float-type gauge includes fragile portions, such as the linkage connected to the float which must be sufficiently delicate to translate vertical displacement of the float to the stationary base of the gauge for measuring the displacement. The fragility of the moving parts makes them susceptible to damage.
Alternatively, a computer may be used to estimate the level, i.e., elevation, of the liquid in a vessel relative to the interior bottom surface of the vessel. In particular, specially designed software may be used to monitor usage and predict when refill or recharging is necessary. Previous liquid usage patterns are considered, as well as weather and other data. While of some use, computers have been found to have limited reliability in predicting the amount of liquid in the vessel at a specific time and, in particular, the time when the vessel will become completely empty if not recharged. Such prediction may be especially difficult when the usage patterns are variable.
While these prior art systems have addressed some of the problems in the art, these systems are expensive to manufacture and greater accuracy is still desired. Therefore, there exists a need in the art to address these deficiencies.
An object of the present invention is to provide a detection system that is more accurate in measuring the material level of a container.
A further object of the present invention is to provide a detection system that is more economical to manufacture.
A still further objective of the present invention is to provide a detection system that provides information for a variety of uses.
These and other uses will be apparent to one of ordinary skill in the art based upon the following written description.